Project Abstract/Summary1 Family-based research has established a foundational understanding that parenting practices facilitate school readiness (e.g., child social skills, academic competence). This evidence has been used to develop prevention programs that facilitate successful entry into formal schooling. However, prevention programs focused on school readiness are not universally effective. Programs must account for multiple contextual factors that shape the development of social skills and academic competence (e.g., child characteristics, parent?child interactions, peer relationships) and include genetic influences to be effective. Genetically informed designs have the potential to contribute to the development of effective prevention programs by providing information about the distinct genetic and environmental influences on child development in two majors ways. The first is by accounting for genetically influenced child characteristics that have been shown to moderate the effectiveness of prevention programs. Social skills, academic competence, parent?child relationships, and peer relationships?all critical to school readiness?have known genetic influences. The second is by accounting for genetically influenced characteristics that have been found to evoke responses from parents and peers and influence the peers children select. The activities in this application will disentangle genetic and environmental influences on children?s positive parent and peer relationships and apply these findings to an existing prevention program. Analysis of a longitudinal prospective adoption design will clarify gene?environment interplay by examining (1) the extent to which positive parent and peer relationships are child, parent, or peer driven; (2) the extent to which genetic influences on child characteristics affect positive parent and peer relationships; and (3) how positive relationships affect later social skills and academic competence. Findings from the first study will then be used to formulate hypotheses for the second study. This translational approach will use an existing randomized prevention program to test whether child characteristics and/or positive relationships (previously identified as genetically and/or environmentally influenced) serve as mechanisms of change for the development of social skills and academic competence. Advanced longitudinal analytic strategies, including structural equation modeling and complier average causal effect, will be used to achieve the proposed aims. The interdisciplinary approach of this proposed study will refine a conceptual model that integrates genetic and environmental influences on child characteristics, parent?child relationships, peer relationships, and child social and academic development. The proposed work will also provide training in child development, gene?environment interplay, translation of findings to prevention science, and prevention methodology. As such, it will facilitate my long-term goal of using a developmentally sensitive and genetically informed framework that can be translated to prevention science to elucidate salient mechanisms to develop, adapt, and evaluate future prevention programs.